Let's talk about the gameplay of O2Jam. As with every VSRG (Vertical Scrolling Rhythm Game), every note corresponds to a music, so as you hit the notes the actual music notes will also be played.
2. Info Panel
4. Skill Rings
An example of the playfield is shown on the picture above.
Combo Count - Your current combo. It says "1219" on the image.
Judgement - The accuracy of the note you just hit. It says "Cool" on the image.
Jam Combo Count - The current Jam combo. It is not shown on the image.
HP Gauge - Your current HP. Every Miss and Bad will drain your HP. Losing HP would kill you (turning your avatar into a jelly-like creature), and instantly end the game (if you are playing solo).
Pills - These helps the player from breaking a combo. Check under the Judgement section for more info.
Jam Meter - This is where most of your score comes from. Check under the Judgement section for more info.
Score - Your current score in the game. It says "530190" on the image.
Title - Title of the current song. It says "Necro Fantasy" on the image.
Equalizer - This is mostly for visual appeal only.
Volume - Volume of your O2Jam.
Skill - These shows the current Skill Rings being used in the game. The person is using the "Random" Skill ring in the image.
Judgement and Combo Panel - Every note hit is recorded here.
Current Song Time - Tells you how long the song has been playing. It says "1:09" on the image.
Song Duration - Tells you how far are you in the song. On the image, It shows as a bar with the "o2jam"" on it.
Difficulty and Speed - This shows you what song difficulty you're currently playing, and the Scroll Speed. It says "HX4", which stands for "Hard" diff and "X4" Scroll speed.
Take note that Scroll Speed only controls how fast the note goes down in the playfield, and not how fast the music goes.
Moving on with the rest of the info on the panel, there's the game score on the right which displays your "Max Combo" achieved, and the four judgements which tells you how accurate you have hit the notes. Everytime you hit a note, your Jam Meter slowly gets filled. Hitting an accuracy will fill up the Jam Meter faster.
Jam Meter needs 25 Cools or 50 Goods to be filled. Every time you fill a Jam Meter, your score increases. The higher the Jam Count, the higher the score increases. A Miss or a Bad will deplete your Jam Meter and break your Jam Combo.
Cool - This means you hit the note accurately.
Good - Not so accurate as Cool.
Miss - Literally, the missed notes -- the notes you were not able to hit. Getting a miss will drain your hp by a certain amount, depending on the song difficulty.
Bad - Now this is a special judgement. Getting a Bad means that you technically hit the note, but it was not on time. This drains far more hp than getting a miss. This makes the player to think twice before hitting randomly on songs that they can't play. Thankfully, there are some way to turn Bads to Cool.
The Pills - These could save your life in O2jam (literally!) by transforming Bads to Cools, at the cost of 1 pill per bad. You can only have a maximum of 5 pills at a time, and you don't get to choose when to use it, so it still doesn't exempt players from mashing their keys. Throughout the song, you will regenerate pills by hitting 25 cools in a row, so you don't have to worry about when to panic or not when notes suddenly come pouring down.
These so called "Skills" will allow you to change the way you play the game. On this specific picture, I am using a "Random ring" skill which randomizes the note pattern in the song. There are more Skill Rings available, and you can put at most 2 Skill Rings of different type.
More info on Skill Rings can be found here: http://ecilasworld.blogspot.com/2014/06/o2jam-skill-rings.html
Here is a high-level gameplay video by Entozer.
If you want to know more, check out these guides!
What is O2Jam? (O2Jam Introduction): http://ecilasworld.blogspot.com/2014/06/o2jam.html
O2Jam Skill Rings: http://ecilasworld.blogspot.com/2014/06/o2jam-skill-rings.html
O2Mania Guide: http://ecilasworld.blogspot.com/2014/06/o2mania-guide.html
O2Private Servers: -Coming Soon!-
Feel free to comment or ask any questions!