Glad you enjoyed it!! :D
Yeah, I agree those purple lizards are a bit tougher than I had intended. I will definitely be making a lot of tweaks to enemy AI as I continue to work on the full game beyond this jam.
As for the map, you should only see rooms you've physically been to. Doors don't really show on the map, but the connected entrances between rooms should so you can see what areas you might not have fully explored yet. In the full game, I'd like to add colored doors and item/secret indicators to make the map more readable.
Hmm I'm not sure about the issue you encountered with the missiles. I'm thinking you were at max missiles already and just forgot to swap weapons (L/C key) as they will not spawn if you're already at max capacity. Or perhaps you just had bad luck. Every enemy type has a different spawn rate for health/ammo and some are low so it's possible to go a screen or two without seeing them. Also, for the exploding enemies, you have to actually defeat them for items to drop as opposed to letting them explode on their own. One suggestion I can offer is to look out for crates as they have a 100% chance to spawn a bunch of missiles when you blast them open.
Thanks again for playing the game and I really appreciate the feedback :)