I've never been a huge fan of Gundam type mecha games (or anime for that matter), but these two high class mecha shmups are quickly winning me over with their incredible soundtracks, and highly detailed hand pixeled renderings.
First up is Rohga Armor Force by Data East (also known as Wolf Fang in Japan). The international version is equivalent to the "special mode" of Wolf Fang (if you hold down buttons 1 and 3 while pressing start on Wolf Fang). Special mode cuts out the story line elements between stages (there is still story chatter at the beginning and ending of each stage), and combines all 4 branching paths to an unabridged 12 mission marathon.
Completing Rogha/Wolf Fang with a single credit is a herculean feat, as the 12 consecutive stages will run you about 60 minutes!
Next up is Cybattler by Jaleco. A vertical mecha shmup, and primary inspiration for Grev's latest (last?) shmup for NESiCAxLive arcade platform and XB360 - Strania.
Jaleco wasn't typically known for releasing very detailed or high quality titles, but they really put everything behind this game. The soundtrack is outstanding, boss designs are innovative, and mecha control scheme quite intuitive with a two button shot/sword and strafe while holding either button down. I'll reserve final judgement until I spend more time with it, but needless to say its quite difficult as I couldn't get past stage 2 boss without a lot of practice.