Hi! I'm Dumple, adjunct professor of Iron Crypticle at Cryptonia U. You may remember
me from such articles as The Ten-Second Rule: When it's okay to eat food off the dungeon floor and Basic Beetle Phylogeny: Exploding bugs and you. In this guide I'll cover the basics of playing (and surviving) in Iron Crypticle, and some of the known secrets.

Read through the instructions on the in-game main menu to get a quick overview.

In addition to moving and shooting, you've got some special moves. They're easy to forget about at first but they are crucial:

• Dash! Space button by default. Useful for getting out of the way of enemies, or getting to
  an item before it blinks out of existence. You can dash through enemies without taking damage.
  The dash takes a couple of seconds to recharge but has no other limits on how much it's used. Get in the habit of using it.
  
• Atomic fist! Shift button by default. Clears out enemies (and bullets) in a circle around you.
  You start with one of these, but you can pick up fist icons to get more. These drop as random pickups, and it seems like they are more likely to drop if your stock is low. A nice touch is that if
  you use this in the very first room in the game, a new one drops - so, try it out!
  
• Scrolls! Ctrl button by default. These have various effects, and generally help with crowd control on the monsters. Once you use a scroll, it's gone, and you'll need to find another before you can use another spell. Scrolls not as reliable as the atomic fist for a quick escape, but they're great on those difficult rooms, like ambush rooms with sorcerors or slimes or red bats[tvtropes.org].

Food chaining is useful for score and key for survival. You'll notice that if you pick up several
food items in a row the first is worth 100 points, the next worth "100 x2" points, the next "100 x3",
all the way up to "100 x8". If you pick up some "100 x8" foods, that unlocks a randomly-chosen stat
upgrade which is permament (within the current run). The upgrade will drop at some random spot in the current room, you just need to walk over and pick it up. The four upgrade possibilities are movement speed (yellow), rate of fire (purple), weapon damage (red), and special weapon duration (blue). As time goes by, you'll need more and more x8 combo items to trigger each new upgrade.

To keep the chain going, keep picking up food:

• Going too long without a pickup breaks the chain, and you have to start it again from 100 x1.
  
• Getting hit breaks the chain
  
• Note that missing a food pickup doesn't break the chain. Even if some foods blink out of existence, your chain continues (as long as you're not waiting too long between pickups)
  
• Picking up coins extends the time limit until getting the next pickup.

More tips:

• If you pick up the basket of plenty, the several groups of food items will drop in the room. Picking up one or more of those groups is a great way to get an 8x combo.

When you start, you have 3 hearts, and 0 of a possible 3 points in each stat upgrade. Your "XP" meter fills up as you score points (through killing monsters and picking up items). Each time the bar
fills up, your XP level rises. When your score reaches a high enough cutoff (e.g. 20,000 for level 2)
you go up an XP level and either your max hearts or your max stats increase. Going up a level doesn't immediately improve those stats...but it raises the ceiling so that you can improve them.

Below is a table of point values and stat boosts by level, taken from a run on normal difficulty:

• In some rooms you'll see a small fist icon in the background art. If you use your atomic fist (SHIFT key by default) on top of the icon, a bunch of bonus food and coins will drop! The icon lights up after you've collected the bonus.
  
• You can collect runes with the letters B, O, N, U, and S. When you collect the whole word,
  all the enemies in the current room will be defeated an replaced with a points item (coins or bells). (After this, your collection resets - you can start collecting runes again, and you can trigger the BONUS again in the same run)
  
• You can collect gems with rainbow colors ranging from red to blue. When you collect all seven,
  a fancy graphic appears, and rainbows (point items) appear around the screen. You also get a rainbow shot powerup that fires off in a random direction; you keep this until you next get hit. (I think it's possible to trigger this bonus twice in run, but not likely - you'll get enough duplicates of the same gem that you'll probably either die or beat the game before the collection is complete)
  
• If you get hit twice in a row, a golden turd icon drops, worth 5000 points. (Consolation prize!)

• In easier rooms (especially on early floors), focus on food chaining, and try to milk each level
  for as many stat upgrades as possible. In more challenging rooms, focus on survival.
  
• Go for arcade rooms when you have the chance. For 10 coins, you get a shot to collect coins, cake (points), and even hearts by playing a mini-game. And, this is one room where you aren't at risk of getting killed. You can get 40 coins back from a typical run (depending on level layout). If you get 3 cake pickups, you'll get a heart, and 6 cake pickups (lucky you!), you'll get 2 hearts. (Thanks GuidoN for the info!) If you fail the arcade game, you can try again (for another 10 coins)
  
• If you don't have the level map yet, and there's no other reason to pick one path over another, pick a next room that gives 2 doors, so you have options.
  
• Shops are useful! Plan your level route to hit shops (the coin icon on the room) when you can. Focus on buying upgrades (especially damage and firing speed). Do buy hearts if you're wounded and late enough in the game that you can't count on healing faster than you take damage. In general, don't buy gems and BONUS runes - save the money for a future shop!

You unlock some more weapons and items by playing the game. I'm not certain what triggers it (maybe score, or XP, or just total number of runs?), but most of the unlocks seem to show up quickly.

If you complete the regular game (defeating the boss of level 4), you unlock New Game +. This is similar to choosing "New Game", but with some updates:

• There are now six dungeon floors in all, with two new bosses in the new floors.
  
• After each boss room (except the last) you visit a bonus room with additional point items
  
• A mini-boss room appears on floors 2, 4, and 6, where you fight two large multi-segment worms.

The full 6-level run takes something like 90 minutes. Assuming you survive long enough, and shop wisely, you can max out your XP and fully upgrade all four stats.

Thanks for reading this guide! Let me know if you spot any mistakes, or have tips to contribute.

Update: After a few attempts, I finally cleared New Game Plus mode! Here's a video of the run: