The game is easy but it's kind of a fun change of pace to be able to upgrade towers and have them kick so much butt. The biggest downfall of the game: All towers can get down to a reload of 8. This is waaaay overpowered for almost all the towers.
Using a noble specializing in big guns I got past level 40 for the first time (currently 47 and breezing through with gravity guns). It's something to give a try (you have to get a gravity gun or grenade launcher early to take care of large groups. I did, anyway :D).
You can also weaken a grinder with the razor sword. It effectively takes 3 hits to kill it once you have the sword (watch out, though, you will change it's course which might knock it off screen or make it hard to get in 2 more hits).
First move of my fight with the Hydra (on an Epic run). I switch swords, use slime bunny... 2 instant deaths spells that land in a row. Game over. You should probably make it so they can't both use the magic, unless you are adamant that we should have auto life on at all times or something. >.>
This isn't a real test of intelligence in any tangible/useful way. Sure, higher scores may represent a better ability to play this game, but I have already gone from getting 100k a game to breaking 400k and then quitting of my own accord.
That doesn't mean it's not addicting. :)
Mars in 2 days. The most important thing is to have a good first day (3k or better). Then you buy a fuel sucker, at least a level 2 radar (although a level 3 helps tremendously) and upgrade your fuel tank as much as possible. Balancing the % increase from higher level fuel suckers and having a large fuel sucker is important.
If you don't get it on day 2, then max your fuel sucker/tank/e-rockets. That should be all you need to get to mars. Aim for the gold/purple platforms and save the rockets for when you don't see at least a green platform to hit. Good luck.
Pull back after the first revenge wave starts, Dolmisu. One Titan spawns per revenge wave, you probably damaged the castle about 2/3 of the way and had more than one revenge wave spawn. I am just now finishing up Trail 4, I fought the Darkness Titan and 3 Blue Dragon Titans. ;)
If anyone is having trouble it is most likely due to the revenge waves. The key is to remember that 3 of those waves will be sent as the enemy castle's HP drops. Get their castle down to about 1/3 and then retreat. Take care of the entire revenge wave before you start damaging the castle again. You run into trouble when you do a lot of damage to the castle and get 2 or 3 waves sent. Then you are facing 150+ units.
If no one else has noticed this, you should upgrade units on the setting they get the most bonuses from. When you level up the increase in damage/hp is a % based on your current stats. The stats appear boosted if they are supposed to be (from the terrain). My pikemen are almost 4 times as strong when I level them up on a plain (as opposed to a mountain).