11. Ultra Gold Medal (25)
-------------------------------
Score 25,000 points playing 1 minute Ultra.
You will have to be somewhat quick for this one. Set your starting level to 10 and go for Back to Backs. You can get it with just two Back to Backs (Three Tetrises). This may take a couple tries, but once you get the level 10 speed down, you shouldn't have too much trouble.
12. Race Bronze Medal (10)
-------------------------------
Clear 40 lines in under 4:00 playing Race (Single Player).
Make sure you set your target to 40 lines; otherwise the game will end before you can even reach your goal. You should be able to get this with your eyes closed, so don't worry about it too much. If you want a little boost set the fill start to 15.
13. Race Silver Medal (15)
-------------------------------
Clear 40 lines in under 3:00 playing Race (Single Player).
Once again set your target to 40 lines and fill start to 15. This shouldn't be too difficult, just try getting the fill out of the way first and then start making your own lines. You can do Tetrises if you want, but they don't really help seeing as score isn't an issue here.
14. Race Gold Medal (25)
-------------------------------
Clear 40 lines in under 2:00 playing Race (Single Player).
This one might take a couple tries, but you should be able to get it. As usual set the target to 40 lines and fill start to 15. Focus on the fill, and try to get as much of it out of the way as possible. Don't worry if you mess up, just focus on clearing as many lines as possible.
15. Score Bronze Medal (10)
-------------------------------
Get 25,000 points in under 10:00 playing Score (Single Player).
I'll leave this one up to you. Just make sure you set the target to 25000, otherwise it will be impossible to get the achievement.
16. Score Silver Medal (15)
-------------------------------
Get 25,000 points in under 7:30 playing Score (Single Player).
Set the target to 25000, and just do a bunch of Back to Backs. You shouldn't have too much trouble trying to beat the time limit. Even if you mess up, you should have plenty of time to spare.
17. Score Gold Medal (25)
-------------------------------
Get 25,000 points in under 4:00 playing Score (Single Player).
Move it! This could quite possibly be the hardest achievement in the game, so this is nothing to mess around with. You have to be fast, really fast, and lucky. There isn't much to know more about this achievement than what it says. Go for as many Back to Backs as possible, without messing up. Make sure to keep your surface as flat as possible, so you will always have a place to put any piece and won't make any awkward shapes you will have to make up for later. It takes roughly around 17 Tetrises in a row, so this will probably take awhile to get down.
18. Hotline Bronze Medal (10)
-------------------------------
Get 25,000 points playing Hotline.
This gametype confused me a bit at first, but once you know what is going on you shouldn't have any trouble. The goal is to clear lines on the various colored lines in the background. The higher colored line, the more points you get. Start with a fill of 14, so that you will be able to reach the highest lines easier. Just focus on clearing the colored lines and you should be fine.
19. Hotline Silver Medal (15)
-------------------------------
Get 50,000 points playing Hotline.
If you are confused about this gametype look at the achievement above. You'll need to start with a fill of 14, so you'll be able to reach the high lines easier. Focus on clearing lines on the blue and cyan colored lines, purple if you get that high. It might be helpful to perform Tetrises consisting of both the cyan and blue line, but it can get a bit risky that high up.
20. Hotline Gold Medal (25)
-------------------------------
Get 100,000 points playing Hotline.
This one might take some tries, but it isn't too hard if you know what you are doing. You might want to put your fill up high, so you can reach the high scoring lines. The best way to do this is to make Tetrises (preferably Back to Back) consisting of two or more colored lines. The higher you are the more points you will get, but also higher the risk. Find a place that you are comfortable with and try to remain there. It might take a bit, but you should be able to reach 100,000 eventually.
Stats as of 9/5/09
Completed XBLA: 103/137
Completed Retail: 75/95
Gamerscore Completion: 95.34%