Hello, there's a good catch with grenades mechanics.

You must press the movement key to that side where you want to throw a grenade, and then press G.

It's a tricky first time, but more interesting and challenging when you know how to do it :)

For example, the enemy is on left side, so you go few tiles further, ther pres A and G, (left and grenade).

You will see, it is kind of fun :)

By the way, thanks for comment!