Pretty alright. At first I found it really hard to kill all the enemies until I found out that if you switch to the proper temptreture, the enemies heal rather than hurt, at which point it became a bit too easy. Ideally the difficulty would be somewhere inbetween. On the brighter side the art is quite nice!

Nice game!

The way you used the concept of heat and cold was good. Just be cautious with the spawning of enemies as sometimes I didn't have the opportunity to defeat them. Try adding more mechanics to make your game deeper, something like changing your proyectiles even after having spawned or special attacks after defeating some enemies. Remember that changing temperature is just one action, so, in my opinion the way you used the limitation was weak.

It's a cool idea, but I feel like the execution was a bit lackluster. Unless I'm missing something, all you have to do is switch which color pellets you're producing when a new enemy appears on screen. The only choice you can make for production is match it with whatever beats the closest enemy or else you'll be defeated (It doesn't help that pellets which do no damage to the enemy disappear when hitting them instead of being saved for future enemies).