I'm looking to run a low-PL, 3rd edition, Supernaturals game with some friends featuring a dark, alternate reality not unlike the Upside-Down from Stranger Things (a reality that looks much like our own, but is filled with all manner of Lovecraft-inspired horrors). Out of curiosity, I decided to look at what it would take for players to bridge the gap from one reality to the other using either Inventor or Ritualist, and was kind of shocked by what I found.
My immediate assumption is that this would be a function of the Movement power (Dimension Travel). "For 1 rank, you can move between your home dimension and one other." Seems like the logical starting spot, and really quite cheap at only 2pp. Maybe even too cheap, but it needs some tweaking.
The default duration for Movement powers is Sustained, which makes sense for many of them, but not if I'm looking to create a device or ritual to transport a group of people from one reality to the other. As I understand Sustained, simply being knocked out would shunt someone out of the Upside-Down and back into our world, which doesn't make a whole lot of sense contextually (unless the device/ritual uses some form of astral projection, with the physical bodies of the travelers remaining in our world). So, we'll slap on the Increased Duration extra to make it Continuous. If the desired effect of the device/ritual is to create some sort of Stargate-esque portal (feasibly the only means of returning home), it might even be subject to a Permanent flaw.
So we're up to 3pp for a Continuous effect, still at 2 pp if it's permanent.
The only other thing I can think to add onto this thing would be Affects Others to make sure the whole party can make use of the device/ritual at once. This would then raise the cost to 4pp for a Continuous effect, or 3pp for a Permanent one.
This still seems ridiculously cheap and easy for what it does. As an Invention, it would only take 3-4 hours to design and 12-16 hours to construct; as a ritual, it would take 12-16 hours to design, and a mere 30-40 minutes to perform! All of this achievable with relatively simple DC 13-14 checks in the appropriate skills.
Maybe I'm wrong, but this seems very cheap and easy to do. Am I overlooking something? Is there something I could be doing to make this more difficult? We're planning to start the game around PL 4, and I know a common M&M guideline for making checks challenging but not impossible is a DC of 10 + PL, but someone who really wanted to max out their Technology or Expertise skill at PL 4 could have a starting skill bonus equal to the DC, granting instant success.
Any insights the folks here have to offer?