Ah, right, alpha channels sound like the easiest method! Forgot about those with all the options
Ok.. a dumb question, but how do I use alpha channels in Construct? Is it somewhere in the picture editor? The wiki doesn't seem to mention anything on it.
Save the image you created with your graphics program (Photoshop or GIMP or what have you) as a .png with the alpha channel built in, then when you have Construct's image editor up, hit Open and select the .png file. The alpha channel will be imported automatically.
In other words, what lucid said
And uh, what's a Line object? Doesn't seem to be in the "Insert new object" list.
Sorry, I forgot there is no Line object in 0.98.9 . It's a 0.99.x feature. It does pretty much what it says... it simply draws a line. You can set the length, width, and color. Not terribly fancy, but useful if all you need is a line.