A very original kind of simulator for sure!
I like the idea of training each recruit in a specialized field so you can really taylor your experience. Unfortunately I kinda messed up from the start so it was hard to recover afterwards, but it was my bad I guess. ^^; One of my guys was low on Stamina and I didn't know how to recover it.
I also really liked how the game keeps opening up, giving you more options as you go, whether it be open new training grounds, take part in competitions and missions, etc.
The pixel art is simple yet effective. Even with such tiny sprites you can tell what they're doing (exercises and such), so it's perfect.
Maybe adding a bit of backround military music would add to the overall experience. Maybe not at all times, but it could like... come and go, without being overly loud, like a fanfare playing in the background, rehearsing far from the training ground?
Overall a pretty solid demo, well done!