The game was extremely easy...
If I can beat it the first time without really knowing what I'm doing, it's too easy. The game is too short as well. I never even used the nuke or the rockets, there was no need for them. The main gun was too powerful against the slow moving Goliaths, and the Mamooths die too quickly to the laser. The weapons are slightly too powerful and the game is too short which is why I'm giving you a 5. It's a good game, just make it longer and tone down the damage on the weapons.