First, you're going to want to reacquaint yourself with the basics. To clear each board, you'll need to hit every orange peg, but to get the highest score, you'll want to go for a ton of skillshots (more on that later), and clear out as many blue pegs as possible before going for the last orange to cause a "fever" and end the level. It's a common misconception that you'll want to clear up every orange peg as fast as possible, and it's the worst way to earn a high score.
Each peg you hit during any given ball launch will increase your multiplier for that one launch, and if you score enough you'll earn a free ball. Hitting an orange peg resets the multiplier, so try and get a handful of blue and purple pegs in addition to orange every time -- that way, you'll be swimming in extra balls and extra points. If you see an errant blue peg directly blocking an orange, instead of trying to bank off into the orange, hit the blue and bank into a bucket for a point bonus and a free ball. In fact, a good rule of thumb is to always aim for the bucket, even if it seems impossible.
For the impatient people out there, hold the X button to speed up the bucket to a specific location. If you hate the layout of a stage right away (basically, if a ton of orange pegs are hidden below waves of blue ones), press the menu button and restart until you get a better one. It only takes a few seconds and can be the difference between a 50,000 and 500,000 point round.
Gnorman's power is probably the best all-around ability, as it allows for a maximum amount of peg collection at all times. If I have a choice between Masters in any given stage, I tend to go with Gnorman. As for Luna's power, it gives you with the unique ability to "ghost" every blue peg on the board for a few seconds, leaving them translucent and open for pass-through points. Don't think of it so much as a way to "get to" oranges, but a way to clear out more blues for points, as her ability "resurrects" blue pegs. If you can help it, save a green peg for the end, as Luna's power pays dividends and has a special payout during the last Fever hit.
If you need to practice for some of the "Ace Score" challenges of 500,000 or more, play Bjorn's trials with the Super Guide until you get the physics down. Although I generally don't recommend Bjorn's power as it has one of the lowest point ceilings, it can be useful at the very end of a stage for banking into the middle 100,000 point bonus cup. As a general rule however, Luna is key for the final Fever Shot.
Peggle 2 also has a number of skillshots. You have the Long Shot (hit a peg, then hit another non-blue peg at a distance), the Free Ball (hit just one peg then land in the bucket), Mad Skills (five free balls in a row, which is easier than it sounds if you're going for it), Extreme Slide (sliding off 12 pegs in a row -- count them before you attempt this), Off the Wall (bank off a side and into a non-blue peg), Kick the Bucket (get the last orange peg off of a bucket bounce -- always go for this at the end), Lucky Bounce (bounce off the bucket, then catch it again for a free ball), and Orange Attack (simply get a ton of orange pegs in one ball). Skillshots not only help you clear the board quickly, but also net you lots of bonus points, so they're good to practice.
Speaking of challenges, some of them will allow you to choose your Master -- but only if you have them unlocked. Try and complete the game first then go back to these trials so you have all the tools you need to conquer them. Having said that, Bjorn's ability is perfect for the low score challenges, as his guide allows you to aim underwhelming shots with accuracy -- which is especially useful for avoiding the final 100,000 Fever bucket. If you want to go strictly for achievements try the Celestial levels, as they have a greater propensity for high scoring antics.
So while Peggle 2 definitely has a lot of the same mechanics as the other games in the series, you'll have to adapt a bit with the new powers and layouts. Just remember to always go for skillshots at every turn, and you'll graduate from the Peggle Graduate Program in no time (it's not accredited, so don't put it on your resume).
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