For all I know the original arcade version of Thunder Blade could have been an amazing action game, but that is certainly not the impression I got while playing this Sega Master System port. There's just no other way to say it, Thunder Blade on the Master System is total trash. In an era full of amazing 2D shooters, this Sega arcade port is hideously unattractive and not worth your time or money.
But let's back up a little bit, there's no reason to spell everything out in the first paragraph. Thunder Blade has a lot of potential; it's a helicopter game that offers two different perspectives. Part of the game is spent overhead, similar to the likes of Ikaruga or countless other classic vertical shooters. The other part of the game attempts to pull off the 3D look, but thanks to limited hardware and terrible controls these sections are rendered practically unplayable. Neither of these sections is very interesting and has been done much better in other games (even other Sega games).
No matter what perspective you find yourself in, Thunder Blade only has two weapons for you to play around with. You have a standard chain gun (that does not have rapid fire capabilities) and a air-to-ground missile, which is used to take out the tanks lining the streets below. Don't look for power-ups or any kind of boost in this game; this is all about making use of the two weapons at your disposal. The biggest problem seems to be that neither of these weapons is very affective. Your chain gun shoots bullets at an extremely slow speed and the missiles can only be launched one at a time, which makes taking out two or three tanks a real pain.
Each level plays out the same; you start with an overhead section and then get warped to a 3D Space Harrier-style sequence. After you've survived those two sections you are introduced to a large aircraft that you must destroy. Once you've done that it's on to the next level, which is just more of the same. To make this even more unbearable, the levels and enemies aren't very diverse. It's not that it's repetitive, it's that it's not rewarding in any sense of the word. You don't really care what comes next and probably won't want to keep playing past the second level.
The difficulty is a good news/bad news sort of affair. It's nice to see that when you die you aren't transported to the beginning of the level (as is the case with so many 2D shooters of the era), but die too many times and it's game over ... for good. Unless you decide to cheat Thunder Blade does not actually have a continue system, so it's up to you to play through the entire game with the few lives you are given at the start. The good news is that after the game is over it will give you some time to reevaluate whether or not you actually want to play this game. Just trust me on this, you don't want to play it, the game is really bad.
The graphics in Thunder Blade aren't bad, but you'll find a lot of repeating characters and background images. The 3D stuff comes off looking a little better than the 2D, but neither really stands out. As you might imagine the 3D effects are pretty poor and the 2D stuff suffers from the occasional slowdown. Of course, none of this really matters much when you're so frustrated by the terrible controls and unfair difficulty level. This is not a game you will want to pick up for the graphics ... and for that matter; this is not a game you will want to pick up at all.
Maybe it's just me, but the Thunder Blade series just doesn't do much for me. I'm not impressed with this terrible 8-bit game, and the first generation Genesis title was a disaster. Perhaps that's why Sega decided to kill the Thunder Blade franchise before they created technology that could actually handle this type of game. As it is this 8-bit Thunder Blade is a muddy mess of bad controls, frustrating game play and uninventive level designs. The only person this game is going to appeal to is the type of gamer who has played every other 2D/3D shooter ever created ... and even that guy may want to think twice about jumping into the cockpit of this awful title.